This module provides functions to format a tree
structure or SAX stream as UTF-8 encoded XML.

The formatting functions always outputs only UTF-8, regardless
of what encoding is specified in the document's XMLDeclaration.
If you want to output a document in another encoding, then make sure the
XMLDeclaration agrees with the final output encoding, then format the
document, and convert from UTF-8 to your desired encoding using some text
conversion library.

The lazy ByteString representation of the output in generated with very
small chunks, so in some applications you may want to combine them into
larger chunks to get better efficiency.